In general, a semiconductor chip (also called die, chip, or microchip) may be processed in semiconductor technology on and/or in a wafer (or a substrate or a carrier). The semiconductor chip may include one or more microelectromechanical systems (MEMS), which are formed during semiconductor technology processing.
During processing, the semiconductor chip may be mechanically stressed. For example, mechanical stress may occur during singulating the semiconductor chip from the wafer, during handling the semiconductor chip by positioning systems (also called Pick-and-Place applications), during thermally treating the semiconductor chip, e.g. during encapsulation or soldering the semiconductor chip. Alternatively or additionally, the semiconductor chip may be mechanically stressed during operation of the readily processed chip. For example, mechanical stress may occur due to thermal fluctuations during operating the chip.
Such mechanical stress (also referred as mechanical load) may be transferred to the microelectromechanical system on or in the semiconductor chip, which may lead to a deformation (also referred as strain) of the microelectromechanical system. The impact of mechanical stress on the microelectromechanical system (or a device operating the microelectromechanical system) may result in an uncontrolled or undefined behavior of the microelectromechanical system, e.g. malfunction or inaccurate function (e.g. measurement results), and/or may even damage the microelectromechanical system. For example, a microelectromechanical system and/or a device operating the microelectromechanical system (especially silicon microphones) is sensitive to stress from assembly or from thermal fluctuations. In other words, via assembly and the bulk of the substrate of the microelectromechanical systems and devices, the stress is coupling into the microelectromechanical system structure causing changes in their structure and their sensitivity. After assembly, the deformation of the microelectromechanical system may remain, which complicates the fabrication of accurate working devices.
Conventionally, chips with microelectromechanical systems are stress decoupled using a compliant chip attach, e.g. silicone glue. This is possible for assembling chips on printed circuit boards (PCB) but is limited in decoupling capabilities and is difficult to transfer to other assembling techniques. Especially, microelectromechanical systems with high sensitivity are affected by the stress arising from assembly.